Voltage issue...

[whtknt2]

Recently I purchased a stock 2004 Silver Marauder with 44,000 miles on it. I've had the vehicle about 2 weeks now and the voltage dips from 14 (seems normal range) to about 10/12 when stopped at a light etc. It's especially bad when any accessories are on like A/C or the defroster. The voltage goes back to 14 when I continue to drive. Sometimes when its down low it spikes back up to normal. Ford has run diagnostic tests and found nothing. The battery and alternator appear fine under their tests. Another independent shop ran tests and they too couldn't find anything. To date they're only suggestion is to install a 200 amp alternator and see if that works. There is no cost to me luckily as the car is under a special 30 day warranty. Anyone have any thoughts as if this might solve the problem or what might be going on? Thanks!

[Spectragod]

Diodes going bad in the alternator, high resistance on your battery cables, loose cables, bad ground(s), Mine had the same problem with 16K on the clock, in my case, it was the alternator. FWIW.

[Zack]

Get a tune with the idle raised, that will help right there.

[Local Boy]

Mine did that too...

Re-charged it...

Then it just went away...


ALOHA

[UncleLar]

Maybe the car has underdrive pulleys on it,Zack's suggestion would cure the problem then.

[Spectragod]

Maybe the car has underdrive pulleys on it,Zack's suggestion would cure the problem then.

Assuming nothing is wrong, and it had UD's, yep, that will fix it. My car had a tune, no UD's and had the same issue, bad alternator.

I would suggest measuring voltages at load, at the battery and at the alternator, see if there are differences, or if the voltage at idle is less than 13.9 VDC.

[musclemerc]

Post a pic of the pullies I bet there underdrive's

[magindat]

Classic UD pulley symptom. Raise the idle. Go on with life.

[whtknt2]

Thanks for the info everyone! I'll look into the alternator again and pulley system along with the idle!

[whtknt2]

Well the shop installed a new 200 amp alternator and the vehicle was still having voltage issues. They checked the pulley's and all seemed stock. When I bought the car it came with a new Optima Red Top battery. They now say after checking some TSB on the car that the battery may not have enough energy in reserve, seems fishy? Instead they took that battery out and replaced it with a traditional lead type much cheaper, sometihng to do with the gel type versus traditional...I've been looking at the few TSB's on this car and can't find any battery related info nor any TSB about alternators that they said they looked at. Scam or no scam, you tell me...thanks

[Bulten Rauder]

Well, it's great you have a nice new 200Amp alternator. The Optima Red Top tells me the previous owner was serious about his battery and they may have had issues?

Take this to a GOOD shop and they should be able to diagnose the problem. It appears you don't want to diagnose/test it yourself?

[whtknt2]

Thanks for your reply. I bought the car through CarMax and only had it for 8 days before the issue. Luckily they have a bumper to bumper 30 day warranty so they did the repairs sort of. They couldn't figure it out so they sent it to Ford and neither could they. So in the end the car ended up at a Fleet specialty shop. I took the car in on March 17 and getting it back April 14. Almost a month...

[UncleLar]

I hope they at least gave you a loaner.

[fastblackmerc]

Well the shop installed a new 200 amp alternator and the vehicle was still having voltage issues. They checked the pulley's and all seemed stock. When I bought the car it came with a new Optima Red Top battery. They now say after checking some TSB on the car that the battery may not have enough energy in reserve, seems fishy? Instead they took that battery out and replaced it with a traditional lead type much cheaper, sometihng to do with the gel type versus traditional...I've been looking at the few TSB's on this car and can't find any battery related info nor any TSB about alternators that they said they looked at. Scam or no scam, you tell me...thanks

Fishy??? you bet. Scam??? +1! Sounds like they don't know what they are talking about. :eek:

The battery is only used to start the car, once started it runs off the alternator.

"They checked the pulleys and they all look stock". Know what underdrive pulleys look like... you guessed it STOCK. Difference is in the diameter.

Bet it has UD 's on it and all you have to do is raise the idle..............

[UncleLar]

Okay,so how about somebody who has a set of stock pulleys laying around measure them and let him know what the diameters are. I can't measure mine on the car because it's already been moved and is in storage.

[SID210SA]

Or it could just be the guage....I had the same issues and mine was tested at the dealer...they said the guage was off and replaced the guage....no more dipping that low although it still dipped slightly under heavy load (A/C, lights, Sound System etc..)
but now I have new real guages instead of the oem dummy guages and no issues at all....

Mike

[ctrlraven]

When I bought miy 04 with 40k miles on it the volt gauge read 12-13 all the time. Took it back to the dealer for them to check it out and they said the alternator was putting out a low charge and would replace it. Since then volts read 14.1-15.1, the colder it is out the closer to 15 volts it goes. Weird I know but as long as it works.

[Taemian]

If your alternator is a 200 amp PPI, be ready for problems down the line. Dave has gone through 2 before they finally admitted on the phone that they don't have the same "overspun" rating as Ford OEM does, and his Trilogy was mostlikely causing them to fail.
We had one blow up with sparks and flames during a dyno pull, and another shortly after that on a WOT run.
Yes, he did tell them he had a Trilogy before he ordered it, and they said no problem. Until he went through 2 alternators!

[jus2rel]

I have had my marauder for about 2 years, when I bought it I noticed the same exact issue, and mine also had a redtop battery already installed. I worked for a car dealership, had all the techs look at it and everyone gave me the same run around ( bad alternator, bad battery or loose ground) I know its not the gauge because at night you can see the headlights dim and brighten while driving, with the pedal steady down the volts will dip to 10-12 and spike at 15 (the lights get nice and bright at 15) Every few months the car will also be completely dead out of the blue, jump start just fine and be good for another few months????

I have taken it to ford time and time again, been through 4 alternators and 4 batteries, had the comp diagnosed several times, all the grounds checked and cleaned, probably spent over $2000 trying to fix the problem. Nothing they have done has made any difference. I did purchase a tune and saw a little difference, being that the idle is raised. Now I just deal with it and keep a jumpbox in the trunk, other than that the car runs beautiful.

PS? I have noticed that when the car gets wet it seems to do it way more frequently. Being that I live in orlando fl, it gets wet quite often, but during the dry time I rarely notice a problem. Im thinking there might be an exposed wire somewhere that is grounding out w the water, where though is the million dollar question

[CKMustangCobra]

Fishy??? you bet. Scam??? +1! Sounds like they don't know what they are talking about. :eek:

The battery is only used to start the car, once started it runs off the alternator.


Where did you learn that? Most modern vehicle electric systems are designed to pull all current/voltage needed from the battery. The alternators only job is to charge and maintain charge in the battery.... not run the car.

[whtknt2]

thanks for the replies...the dealer took out the 200amp alternator (wasnt working right) and put back the original. They replaced the red top battery with an Interstate Mega Tron which improved the issue a bit. Needless to say it still drops at idle stopped with accessories on (12 to 11 volts). 14 normal voltage while driving...I can even see the voltage meter bounce a bit when applying the brakes...very odd. Oh well no one can find anything and the gauge has been replaced. All I've heard from Ford and others is I have a Marauder with an anomaly. I greatly appreciate everyone's input though, thanks!

[pez]

Mine's been doing the same thing since day 1... What really bothers me is the flickering dash lights - mine are set at about 1/3 brightness and they flicker badly in gear, stopped, as the voltage dips. Also noticed the higher voltage when cold... Replaced battery, alternator, LCM (found a TSB that mentioned a newer LCM revision corrected the flicker at low voltage).

Same problem. Drives me crazy. I'll be flashing it with a new tune for a higher stall TC and plan on asking for a higher idle.... Any thoughts on what sort of RPM idle I should ask for?

Cheers,
Colin

[DEFYANT]

A corroded negative cable could cause this. Go over all the connections at the battery, alt, and where the negative cable is grounded. And just for good measure, the cable my LOOK ok, but under the sheathing, it may be corroded.

My alt gauge hangs around the 15 - 16 volts. But I am running a different guage and have modified the primary red wire on alt.

Good luck.

[MJOR]

I had the exact same problem with mine - eventually it got to the point that when I hit the brakes the engine would cut out! And then I couldn't even get it to restart. I took it to Muzi Ford who replaced a couple of non-electrical items (I don't recall, I think IAC was one of them) and it turned out to be a chafed wiring harness.

They replaced the main engine wiring harness (under my extended warranty thankfully) and now my gauge stays steady and my dash lights/headlights don't dim or flicker anymore when I'm idling or braking. Back when I posted this problem, a lot of other members had problems with the wiring harness getting pinched/rubbed somewhere. Pop your hood and look over all the wiring. You can go around in circles forever replacing the "standard" electrical components (battery, alternator, etc.), but if you keep swapping them out with the same results, your problem is somewhere else (and probably more expensive).

[CKMustangCobra]

I had the exact same problem with mine - eventually it got to the point that when I hit the brakes the engine would cut out! And then I couldn't even get it to restart. I took it to Muzi Ford who replaced a couple of non-electrical items (I don't recall, I think IAC was one of them) and it turned out to be a chafed wiring harness.

They replaced the main engine wiring harness (under my extended warranty thankfully) and now my gauge stays steady and my dash lights/headlights don't dim or flicker anymore when I'm idling or braking. Back when I posted this problem, a lot of other members had problems with the wiring harness getting pinched/rubbed somewhere. Pop your hood and look over all the wiring. You can go around in circles forever replacing the "standard" electrical components (battery, alternator, etc.), but if you keep swapping them out with the same results, your problem is somewhere else (and probably more expensive).

Remember where the harness was chafed at? What a pain in the dick to fix an issue.

[MJOR]

The dealership said it was chafed somewhere around the front bumper, but they seemed to tell me something different every time I called.

Once they replaced the harness I couldn't believe how much better everything was though. When I first got the car I thought that the electricals were just poorly designed - turns out that sometimes they're just poorly assembled.

I guess it could be pulleys too, but if everything else in the car looks bone stock (whtknt2's car) I doubt someone would change just the pulleys.

[CKMustangCobra]

Thanks bud

[BirchMarauder]

Where did you learn that? Most modern vehicle electric systems are designed to pull all current/voltage needed from the battery. The alternators only job is to charge and maintain charge in the battery.... not run the car.

ok so you just admitted that the car gets it power from the alternator which is charging the battery. So I guess the alternator is running the car after all. wonder what would happen if you disconnected the battery while it was running?? Maybe..... nothing. You're pretty silly man.

[CKMustangCobra]

ok so you just admitted that the car gets it power from the alternator which is charging the battery. So I guess the alternator is running the car after all. wonder what would happen if you disconnected the battery while it was running?? Maybe..... nothing. You're pretty silly man.

Alternators are meant to maintain battery voltage, not run the car. The batteries job is to run the car.

Unplug the alternator while it's running. Maybe nothing. You're pretty silly man.

[HWYSTR]

Have an issue with the charge light intermittently coming on, did a search regarding alts and came up with this post. The car in question has at idle from day-one (one owner) showed low voltage, and with accessory load shown light-flicker (dash/headlight/etc). Have a few comments and questions:

MJOR - You mentioned somewhere around the front bumper they said? Like forward light harness? I believe the alt is wired through the main engine harness, though a headlight or fan short could cause similar issues. Did they replace the entire harness (engine and forward light)? Do you recall?

Optima / Gel-cell batteries- They are very sensitive to shorts, and a short cooks cells. Once you cook a cell, the battery SEEMS fine, will charge, but it's capacity is compromised. The only way to tell is by putting it on a 'smart' charger, which will throw an error during a charge if a cell is cooked.

Red Tops/Yellow Tops - Red Tops are ok for imports, only buy the Yellow Tops for these cars. The yellows are deep cycle, and have less of a drop-off under continuous load, and low temps. There's a big difference.

Alts / high output Alts - Total / peak amp rating isn't what's important, but output at the load speed. A 200a alt in most cases has the same output at idle as a factor one. The police/fire/rescue alts put out more at idle where it counts. When shopping for a performance alt, ask for an output chart that shows output across an rpm range.

Changing the idle speed only masks the low output at low speed. You'd be better off changing the pulley on the alt so it turns faster at idle, like maybe a pulley off a CVPi. I'd like to think that Ford saw the deficiency and replacement alts have a better output at idle. Of course, if it's due to a short like in MJOR's case, increasing output will only cook other stuff faster.

PEZ - What's the TSB number for the LCM upgrade/repair?

Battery/Alt runs a car - Load-sensing alts, or a better example, one-wire alts, need a battery to excite (charge). If you disconnect a batt on these types of alts, the car will run, but it can go into a full-charge state and in short order cook itself. From an engineering standpoint, like from a design perspective, the alt is only there to charge the battery, the battery itself is the power source for the circuit. (obviously, this is a simple explanation)